Pour 1¼ cups hot brewed coffee into a shallow bowl and whisk in the espresso powder until dissolved. Add up to another ¼ cup coffee in place of the bourbon from the original recipe. Set aside to cool slightly.
Place the room-temperature mascarpone in the bowl of a stand mixer fitted with the whisk attachment. Gently stir with a flexible spatula first to loosen the mascarpone.
Add the brown sugar, cinnamon, ginger, nutmeg, cloves, and kosher salt.
Whisk on medium speed just until the ingredients are evenly combined.
Add the alcohol-free vanilla extract.
Pour in the heavy cream in two additions, whisking between each addition until incorporated.
Add the pumpkin puree and continue whisking on medium speed until the pumpkin mascarpone mixture reaches soft to medium peaks. Avoid overwhipping.
Quickly dip half of the ladyfingers into the coffee mixture one at a time for approximately 2–3 seconds each.
Arrange the soaked ladyfingers snugly across the bottom of a 2-quart rectangular baking dish, breaking individual pieces when necessary to fill gaps.
Spread half of the pumpkin mascarpone cream evenly over the ladyfingers.
Dip the remaining ladyfingers into the coffee and arrange them over the cream.
Spread the remaining pumpkin mascarpone mixture evenly over the second layer and smooth the surface with a spatula.
Cover the Pumpkin Tiramisu tightly and refrigerate for at least 4 hours, preferably overnight.
Immediately before serving, use a fine-mesh sieve to generously dust the surface with Dutch-process cocoa powder.
Slice or scoop into individual portions and serve chilled.